Heating flue installation for baking ovens



lvOV.v 10, n W. OTTO HEATING FLUE INSTALLATION FOR BAKING OVENS FiledApril 30, 1930 2 Sheets-Sheet 1 lli- /ess-es: A fare/:for:

Nov. 10, 1931. w.'o'r'ro '1,831,768

' HEATING' FLU INSTLLTION FOR BAKING OVENS Filed April 30. 1930 2Sheets-She-et 2 Mfr/eases: 1 ,fn

Patented Nov. 1o, 1931 UNITED s'rpxrnsv WILHELM or'rdgor BERLIN, GERMANYVIIisxA'IINer ILUE INSTALLATION nonv BAKING o VENs Application led April30, 1930, Serial No.

The main problem of the heating of baking ovens consists in that theheat produced in the combustion room is transmitted upon the walls ofthe baking chamber with maxi- 5 mum drop` of temperature and absolutelyv uniformly.

The question of heat eXchange has been solved by the water heatingtubes, this system permitting however to produce only little temperaturedifference between the baking chamber and the heating bodies of thesame, as the critical temperature of the water requires certainlimitations. In the other known systems the heat exchange is attained insuitable limits either by great accumulating masses or by heatthrottling, this being, however, connected also with considerable lossesof heat.

Counter-current heating arrangements, in which for instance on theforward travel of the heating gases the ceiling of the lower f hearthand at the backward travel the floor of the upper hearth is heated, havebecome known, also brick ovens, in which the fines extend forward andbackward in zig-zag. Unknown was however an arrangement, in which theheating effect of the forward flowing heating gases acted preponderentlyupon the back flowing gases to prevent the same against a drop oftemperature notwithstanding the delivery of heat.

This invention relates to a heating arrangement of baking ovens, inwhich the heating gases are conducted in such a way that the forwardandbackward-movement of the same'takes place between an outer wall, whichis not well heat conducting and a wall adjacent to the hearth whichfavors the heat radiation.

Severalembodiments of the invention are illustrated by way of example inthe accompanying drawings in which Fig. l shows the furnace o oven inlongitudinal section.

Fig. 2 is a similar view showinga double sided arrangement of theheating flues.

Fig. 3 is a similar view showing a modiflcation of Fig. 2,

Fig. 4 shows in longitudinal section the two main fines.

f the baking Marca-ana in ,Germany April 29, 192s.

Fig. 5 shows a flue of vundulated sheet metal plates. i Y Fig. V6 showsa flue of undulated vsheet metal plates andl refractory material.

Fig. 7 shows in side elevation and `55 Fig top plan'view av third form,0f constructionk of the heating plant.

Referring to Fig. l the outer wall, which is abad conductorof heat, isdesignated by d, and Vdesignates the' wall adjacent to the `60 hearthwhich favors the ,heat radiation. A partition L, situated between thetwo lues serves to ensure the correct heat delivery from kthe forwardflowing heatingl gas t0 the backward flowing heating gas, whereby 55maximum heat drop., perfect equalization 'of temperature and favorableheat delivering to the baking chamber are obtained, that is ,best heatoutput from the fuel.

Fig. 2 illustrates a double sided arrange- 70 ment of the heating flues.The reversing lpoints are situated approximatelyat the centerof thehearth. Bymeans of gas kburners r arrangedjin'the distribution channelsa the productloIlQof the heating gases takes place 75 -directly beforevthey enter into the channel o.

The'channels I; are designed for collecting and conveying the/wastegases.

In'erder to better utilize the heating gases,

the twolvateral discharge channels?) maybe 30 united, as shown i-n fFig. 3, vbelow the hearth floor to a common channel b1,lv so that thereturnchannels ,c extend along the sides of the hearth to below and thenunder the floor to the common vchannel bl.

Instead of the heat insulating layer 'a the same arrangement as in thehearth ceiling mayv be provided under thehearth floor s, the return iiowof the heating gases passing again close to the hearth room. f 99 Fig. 4shows a longitudinal section throughV the main channels a and b. Thecross sections of the channels widen towards theiropen ends, in order topreserve at all points uniform speed of the heating medium. 9

As shown in Fig. 5, the return channels or flues o may be built ofundulated sheet metal plates. For higher temperatures they arepreferably made of refractory material, such as chamot or the like, orthey may be made of both materials combined, as shown in Fig. 6.

In Figs. 7 and 8 a heating arrangement is shown in side elevation andtop plan view in stretched, not yet reversed form. The

open ends of the main channels a and b are situated at two diagonallyopposite corners of the developed surface. The distances between theopen ends are therefore over all branches c of the same dimensions, sothatthey exert the same heating effect upon the baking chamber. Uniformdistribution of the heating medium in the one direction and maintainingconstant of the temperatures in the other direction of the heatedsurface ensure therefore a uniorm'baking-heat through `the whole hearth.

If hot air or gases from combustion of any v kind are to be used for'heating, they are 2o supplied into the channels a instead of the gasburners?1 and the air for combustion for the same.

Vhat I claim, is:

l. A heating flue installation for baking ovens, comprising incombination with the baking chamber, heat supply channels in the ceilingof the baking chamber, lateral branches extending from the saidchannels, baking spaces, lnsulated walls arranged above 'the saidbranches, and waste gas channels disposed in the lower portions of thesaid baking spaces, the Vsaid branches extending forward, downward andbackwards between the said walls and baking spaces and opening withtheir lower endsinto the said waste gas channels.

2. A heating flue installation according to claim l, in which the crosssections of the heat supply and waste gas channels gradually expandtowards their open ends on the op- Q posite side.

3. A heating flue installation according to `l claim l, in which thelateral branch channels positioned between the heat supply and waste gaschannels consist of a diathermic material. In testimony whereof I havehereunto Set v my hand.

WILHELM OTTO.

